Bellows pump



Nov. 15, 1960 D. E. LUPFl-:R ETAL 2,960,038

BELLOWS PUMP 2 Sheets-Sheet 1 Filed April 18, 1955 MEASURING MEANS Mamma..

REGENERATION CHAMBER 2 Sheets-Sheet 2 Nov. 15, 1960 D. E. LUPFER ETAL aELLows PUMP Filed April 1a, 1955 mwsm www@ D.D.E. W ,4.42m i L m TA1 MR w a. 4. www. m m m fwn F F a BELLOWS PUMP Dale E. Lupfer, Daniel M. Vesper, and Emmerich Guenther, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Filed Apr. 18, 1955, Ser. No. 501,934

1 Claim. (Cl. 10S-38) This invention relates to bellows pumps. In another aspect it relates to pneumatic actuating systems for bellows pumps.

In various chemical operations there is a need for pumps which are capable of delivering accurately measured quantities of liquids. For example, a photometric analyzer has recently been developed which utilizes the change in color of a liquid reagent when contacted by a test gas as the basis for detecting the gas. The liquid reagent is directed through a first optical cell prior to its contact with the gas. The contacted reagent is then directed through a second optical cell. The color of the reagent before Contact with the gas is compared with the color of the reagent after Contact with the gas. The accuracy of the analysis depends upon maintaining a constant flow of the reagent through the system. Commercially available pumps have not proved satisfactory for use in this analyzer because they have not been able to maintain a constant flow over an extended period of time.

In accordance with the present invention there is provided an improved pneumatically operated bellows pump which is capable of maintaining a constant liquid flow. The assembly is provided with rst and second stops which regulate the stroke of the bellows. The bellows is compressed by air under pressure to eliminate mechanical driving means. This greatly increases the accuracy of the pump over an extended period of time. Novel means are provided to introduce the compressed air into the pump body and to exhaust air from the pump body at a predetermined frequency. These means are in the form of a motor-driven air valve or an electrically operated three-way solenoid valve. Each stroke of the bellows forces a predetermined volume of liquid through the pump.

Accordingly, it is an object of this invention to provide an improved bellows pump which is operated by a source of pneumatic pressure.

Another object is to provide a motor-driven valve to supply air under pressure to and exhaust air from a bellows pump at a predetermined frequency.

-Another object is to provide a three-way solenoid valve system to supply air under pressure to and exhaust air from a bellows pump at a predetermined frequency.

Other objects, advantages and features of the invention should become apparent from the following description, taken in conjunction with the accompanying drawing, in which:

Figure l is a schematic View of a photometric analyzer having the bellows pump of the present invention incorporated therein;

Figure 2 is a detailed view, shown partially in section, of the bellows pump;

Figure 3 is a view, shown partially in section, of a rst embodiment of the pneumatic pressure supply control system;

Figure 4 is a View taken along line 4 4 in Figure 3; and

States Patent O lCC.

IFigure 5 is a schematic view of a second embodiment of the pneumatic pressure supply control system.

Referring now to the drawing in detail and to Figure l in particular, there is shown a photometric analyzer in which the bellows pump of the present invention is particularly useful. This analyzer is adapted to measure the oxygen content of a gas stream which is introducedinto a liquid-gas contacting chamber 10 through a conduit 11. The gas is vented from chamber 10 through a conduit 12. A liquid reagent, which advantageously is an alkaline aqueous solution of sodium anthraquinone-beta-sulfonate, is directed from a regeneration chamber 13 through a conduit 14 which communicates with the inlet port of a bellows pump 15. A mass of zinc amalgam 17 is supported in chamber 13 by a screen 1S. The sulfonate solution is reduced when contacted by the amalgam and acquires a deep red color. A conduit 20 communicates between the outlet port of pump 15 and the inlet port of a cell 21. A conduit 22 communicates between the outlet port of cell 21 and the liquid inlet of chamber 10. A lter 23 is disposed near the bottom of chamber 10. This filter is permeable to gas but impermeable to liquid. The liquid and gas introduced into chamber 10 ascend together so that the sulfonate solution is partially oxidized by oxygen present in the gas stream introduced through conduit 11. The red color of the sulfonate solution is reduced in intensity in proportion to the amount of oxygen in the gas sample. The sulfonate solution is removed from chamber 10 through a conduit 25 which communicates with the inlet port of a second cell 26. A conduit 27 communicates between the outlet port of cell 26 and the top of regeneration chamber 13.

A rst beam of radiation from a source 29 is directed through cell 21 to impinge upon a photovoltaic cell 30. A second beam of radiation from source 29 is reflected by a prism 31 through cell 26 to impinge upon a second photovoltaic cell 32. Cells 30 and 32 are connected in opposition to a voltage measuring means 34. The indicated signal is thus representative of the difference in radiation transmitted through cells 30 and 32. This in turn isa measure of the change in color of the sulfonate solution when oxidized by the gas being detected.

The apparatus is arranged such that the sulfonate solution returns to chamber 13 from chamber 10 by gravity ow. It is essential that the reagent be circulated at a constant rate to provide an accurate measurement of the oxygen in the test gas. The test gas must also be directed through chamber 10 at a constant rate. Bellows pump 15 is provided to circulate the sulfonate solution.

Pump 15 is illustrated in detail in Figure 2. A cylindrical hollow pump body 40 defines -a bellows chamber 63. A base 41 is secured to body 40 by a plurality of screws 42. A gasket 43 is interposed between base 41 and body 40. A nipple 44', having a flanged lower portion, extends through a central opening in the top of body 40. A lock nut 45 is threaded to nipple 44 to retain the ilanged portion thereof in engagement with the top of body 46. A gasket 46 is interposed between the anged portion of nipple 44 and body 40. A set screw 47 prevents nipple 44 from rotating. A bellows 48 is positioned within valve body 40 and is secured at one end to nipple 44, as by soldering. Bellows 48 prefenably is made of metal, but can be formed of fabrics for some applications. The second end of bellows 4S is secured to a plug 49. A conduit 50 is secured to the top of nipple 44 by a cap 52. The second end of conduit 50 communicates with the interior of a check valve housing 53. A nipple 54 is threaded to one end of housing 53 and a nipple 55 is threaded to the second end of the housing. Nipple 54 is threaded to form the inlet port 56 of the pump, and nipple 55 is threaded to form the outlet port 57 of the pump. A ball 58 is positionedl within nipple 54' to forma lirst check valve, and a ball 59 is positioned within nipple 55 to form a second check valve.

A passage 61 is drilled in base 41 to communicate between an air supplying conduit 62 and chamber 63. The introduction of air into chamber 63 compresses bellows 48. The amount bellows 48 is compressed is determined by the setting of a cap 64 which is threaded to base 41 and retained in place by a lock nut 65. A rod 67 extends through cap 64 and base 41 and is threaded to a lock plate 68 and plug 49. A plurality of holes 69 is formed in plate 68 to transmit pressure from passage 61 to chamber 63. A stop member 71 is attached to the lower end of rod 67 by a screw 72. The upward movement of rod 67 is thus terminated when member 71 engages cap 64. The length of the compression stroke of bellows 48 v can readily be adjusted by movement of cap 64. A com- 'pression spring 74 is positioned within chamber 63 to retain bellows 48 expanded in the absence of iluid pressure being applied to the chamber. ln some applications this spring is not needed because bellows 48 tends to remain expanded.

Air under pressure is supplied to chamber 63 periodically through conduit 62 by the valve system illustrated in Figures 3 and 4. A valve body 80 is secured to a plate 81 by Supports 82. Valve body 80 has a central passage 83 therethrough into which is inserted a plunger 84. Three spaced ports 85, 86 and 87 communicate with passage 83. Conduit 62 is threaded into center port 86. A compressed air supply conduit 88 is threaded into port 85, and a vent conduit 89 is threaded into port 87. A portion 90 of plunger 84 is of smaller diameter than the remainder thereof. When plunger 84 occupies the illustrated position, ports 86 and 87 are in communication and ports 8S and 86 are separated by plunger 84. The diameters of ports 85, 86 and 87 are greater than the diameter of plunger 84 so that the pneumatic pressures in the ports are applied `to all sides of plunger 84 to prevent binding. A slotted plate 92 is secured to one end of plunger 84 by screws 93. The slot 94 of plate 92 extends in a direction perpendicular to the longitudinal axis of plunger 84. A synchronous motor 96 is mounted on plate 81. A ange 97 is secured to 4the drive shaft of motor 96 by a set screw 98 and a pin 99 is attached to ange 97 near the periphery thereof. This pin extends into slot 94 in plate 92. Thus, rotation of motor 96 results in rotation of pin 99 to move plunger 84 back and Vforth in valve body 80. Recess 90 of plunger 84 moves so that port 86 alternately is in communication with port 85 and port 87.

The operation of the pump should now become apparent. With plunger 84 in the illustrated position, bellows 48 is expanded by the force of spring 74. Air in chamber 63 is vented through passage 61, conduit 62, connected ports 86 and 87, and conduit 89. At this time, the uid being pumped enters the interior of bellows 48 through check valve 58 and conduit 50. During the following portion of the cycle, plunger 84 is moved so that ports 85 and 86 are in communication. This applies pneumatic pressure to chamber 63 to compress bellows 48. T'he compression of bellows 48 forces the liquid therein through conduit 50 and check valve 59 to outlet port 57. The cycle then repeats. It should be evident that the rate of pumping is a function of both the length of the compression stroke `ot' bellows 48 and the frequency of movement of plunger 84. The length of the stroke is adjusted by cap 64. The frequency of movement of plunger 84 can be regulated by the use of a variable speed motor in place of synchronous motor 96 or through the Vuse of gears between the motor and iange 97.

A second embodiment of the pneumatic control system is illustrated in Figure 5. Air under pressure is supplied to the irst outlet port of a two-way solenoid valve 100 by a conduit 101. The inlet port of valve 100 is connected by conduit 62 to pump 15. Valve 100 is actuated by electrical pulses Ifrom a timer 103, .In the absence of current being supplied to valve 100, conduit 62 is in communication with a conduit 102 that is connected to the second outlet port of valve 100. Chamber 63 of the pump is connected to vent conduit 102 at this time. When the valve is energized by current being supplied thereto from timer 103, conduits-101 and 62 are in communication so that compressed air is supplied to the bellows chamber of pump 15. The frequency of the operation of valve by timer 103 thus regulates the rate fluid is passed by pump 1S. Timer 103 can be any known type of instrument, either electronic or electro-mechanical, which supplies electrical signals of suiiicient magnitude to operate the Ysolenoid valve. If desired, the frequence of timer 103 can be varied to vary the rate of pumping.

From the foregoing description it should be apparent that there is provided in accordance with this invention an improved pneumatically operated bellows pump and a pneumatic control system therefor. This pump delivers accurately measured volumes of liquid, and does not employ mechanical driving elements which are likely to wear to destroy the accuracy of the pump. The speed of the pump can be maitained constant by the use of a small synchronous motor. The motor need not be large, because it is used only to move a pneumatic valve. The primary operating energy is supplied by the pneumatic pressure. This pressure need not be absolutely constant because the length of stroke of the pump is controlled by the stops on the pump, and the speed of operation is controlled by the synchronous motor.

While the invention has been described in conjunction with present preferred embodiments thereof, it should be apparent that the invention is not limited thereto.

What is claimed is:

A pneumatically operated bellows pump comprising a hollow cylindrical pump body having a iiuid passage in one end thereof, the second end of said pump body being provided'with external threads, iirst conduit means communicating with said fluid passage, a first check valve in said first conduit means to permit fluid ilow through said first conduit means toward said fluid passage, second conduit means communicating with said rst conduit means between said uid passage and said rst check valve, a second check valve Yin said second conduit means to permit fluid ow through said second conduit means away from said fluid passage, a bellows positioned within said pump body and secured to said one end so that said iiull/ passage communicates with the interior of said bellows, a plate secured to the second end of said bellows, a spring extending between said plate and said one end of said pump body to urge said bellows to an expanded position, a rod attached to said plate and extending therefrom through the second end of said pump body, a iirst stop member secured to the second end of said rod, a second stop member threaded to the external threads of said pump body so that the distance between the stop members can be varied, a lock nut threaded to the external threads of said pump body to retain said second stop member in position, and means forming a second fluid opening in said pump body so that the introduction of pneu-matic pressure into said body through said second opening compresses said bellows until said stop members are in engagement.

References Cited in the iile of this patent UNITED STATES PATENTS 253,683 Catterall et al Feb. 14, 1882 862,867 Eggleston Aug. 6, 1907 1,067,613 Lane July 15, 1913 1,072,636 Mueller Sept. 9, 1913 1,623,049 Dorsey Apr. 5, 1927 1,641,280 Joslin et al. Sept. 6, 1927 A1,836,344 Stokes Dee. 15, 1931 (Other references on following page) UNITED STATES PATENTS 2,613,610 Saalfrank Oct. 14, 1952 1,843,545 Redmond Malg, 1932 2,675,758 Hughes API- 20, 1954 1,925,208 Mantle Sept, 12, 1933 2,699,119 Healey Jan- 11 1955 2,126,092 Corydon et e1 Aug, 9, 193s 2706950 Becker APf- 26 1955 2,186,972 Houender et a1 1an. 16, 1940 5 24711134 HPgheS June 21, 1955 2,254,539 Manox sept. 2, 1941 2,731,906 Klug 1an- 24, 1956 2,311,229 Herbert Feb, 16, 1943 2,732,127 Booth 1an- 24 1955 2,455,837 Waldie Dec. 7, 1948 2,501,004 Reese Mar. 21, 195o FOREIGN PATENTS 2,534,504 Engstrom Dec. 19, 1950 10 782 Great Britain Apr. 1, 1853 2,572,390 Righton Oct. 23, 1951 370,842 Great Britain Oct. 24, 1931 

